The Foley catheter, named for Dr. Frederick Foley who first described a self-retaining balloon catheter in 1929, has been in use since the 1930's, in a form nearly identical to its early models. In its most basic form, a Foley catheter has a proximal portion that remains outside the body, a length that traverses the urethra, and a distal end that resides in the urinary bladder. The Foley catheter is held in place by an inflatable balloon that stabilizes the device in place, and prevents inadvertent withdrawal from the bladder. A typical Foley catheter includes at least two lumens along its length; one lumen serves as a conduit that drains the bladder, and the second lumen serves as an air conduit that allows the balloon to be controllably inflated and deflated.
Various developments have added diagnostic functionality to Foley type catheters, including the ability to measure pressure and temperature. For example, U.S. Pat. No. 5,389,217 of Singer discloses a catheter with oxygen sensing capability. U.S. Pat. No. 5,916,153 of Rhea and U.S. Pat. No. 6,434,418 of Neal both disclose a pressure sensor associated with a Foley type catheter. U.S. Pat. No. 6,602,243 to Noda discloses a temperature sensor associated with a Foley type catheter.
The Foley catheter, widespread in use, having a low cost, and easily put in place by health care professionals may offer still further opportunity as a vehicle for deriving critical diagnostic information. The technology disclosed herein provides for the delivery of highly resolved and previously unavailable diagnostic information, as may be derived from a Foley catheter with pressure sensing capability.